The search method he employed was not within the real world, because the barriers between the universes in the real world are more robust. If he wanted to search, he could only travel to that universe and activate the machine.
But in the Dreamworld, it was different. All universes shared a common Kingdom of Dreams, where the dream bubbles of each cosmos were amassed like a massive database. He chose to search for the brainwaves he wanted here.
During the experiment, he had encountered a problem, namely that the virus frequencies used to counter brainwave contamination could not be fabricated out of thin air. The viruses he created were either unusable or uncontrollable.
In the end, he discovered that the best virus was himself.
To be precise, his brainwaves possessed extremely unique properties, different from Batman's and also different from Joker's, but they shared common characteristics with both, which were extremely fatal contaminants for any Batman.
However, these brainwaves could only have one special carrier: his blood. It seemed that only the blood that was a fusion of Batman and Joker could carry the combined brainwaves of both.
Thus, he fashioned these blood-borne brainwaves into a special contaminant. The best solid medium for attachment and propagation was metal; by releasing this metal into other universes and ensuring they were constantly in contact with Batman, they would become contaminated.
The principle of the broad-spectrum brainwave search device he invented was similar. Because it possessed both Batman and Joker's brainwaves, it could easily match which segment of the brainwaves in a certain universe belonged to Batman and Joker.
As a result, it could analyze the state of Batman and Joker in that universe, categorizing them separately and selecting those that were useful to be included in his own plans.
During the search, he discovered a unique individual who not only had Batman's brainwaves but also Joker's, with an 80% similarity to his own. The only difference, that 20%, was probably because the two sets of brainwaves had not merged with each other but were very close and entangled, influencing one another.
Through the reading of brainwaves, he gained a general understanding of the story of this universe. He found the contradictory entanglement of father and son very interesting and thus included them as protagonists in his plan.
After Dream God Morpheus left, the main authority in the Kingdom of Dreams was vacant, but Constantine and Shiller had always possessed a part of the authority. Although it was not as complete as a full Dream God, they still had a certain degree of control over the Kingdom of Dreams.
If using cats to lay the groundwork in reality, making Cat City Gotham a fissure and loophole in the Kingdom of Dreams could still be considered petty thievery, then conducting broad-spectrum searches within the dream bubbles of various universes was outright robbery.
Almost at the same time that the Arkham Universe was noticed and scripted into the play, Constantine discovered that he could sense some special signals in certain regions of the Kingdom of Dreams. He understood the existence of the broad-spectrum search device in a more magical way.
If one were to replace brainwaves with souls, then this search device resembled an Array for finding special souls. Although Constantine could not find the location of this Array or understand its specific principles, he could pinpoint its target by the energy fluctuations it emitted and where it lingered the longest.
Constantine locked onto the Arkham Universe and realized that someone capable of searching for souls had set their sights on it. He shared this information with Shiller, but Shiller did not act rashly.
"So you also knew early on that I had my eyes on this universe," Bruce said.
Shiller nodded slightly, advanced the reel in his hand to the latter half, and said, "And King Robin..."
"He is also one of the targets I found with brainwaves similar to mine," Bruce simply said, "Annoyingly similar..."
In his search, he found not only the Arkham Universe but also several universes with brainwaves partially similar to his. The universe where King Robin resided was one of them.
However, King Robin was not a fusion of Batman and Joker; he was more like a Batman who had become Joker, or a Batman who was inherently a criminal. His memory, thought processes, and behavior patterns bore similarities to a fusion of Batman and Joker, naturally falling within his scope of interest.
When he found King Robin, he realized that although this rascally kid was very much like him, even to an annoying extent, he indeed possessed real talent.
The tools in King Robin's belt were genuine Divine Artifacts. Having such a weapon would make his plans proceed more smoothly.
But such an annoying existence could not play a main role in his drama, so a buffoonish clown for the opening act was an excellent choice.
After reading King Robin's brainwaves, he understood that this guy looked down on everyone and was discontent with himself as well, so he deliberately instigated conflict. Yet he made King Robin helpless against him, and then led him to believe that he was so special because he was a fusion of Batman and Joker.
He then guided King Robin to the Dreamworld, letting him discover that in some ancient universe, Batman's brainwaves had also merged with Joker's. Naturally, King Robin would seek a way to reach this universe.
King Robin released a wave of special energy into the Gotham underground of the Arkham Universe, meant to serve as a fuse for opening the portal. Meanwhile, the mastermind who had been hiding behind King Robin mixed their own Dreamworld channel-opening fuse into it.
Thus, Poison Ivy detonated two portals at once, the first being the portal from which King Robin had emerged, and the second leading into a brand new Dream Bubble in Cat City Gotham within the Kingdom of Dreams.
"And upon King Robin, you've set up even more arrangements." Shiller changed to a new reel of film, which first showed the figure of King Robin standing before a certain pool.
All Robins arriving at the base had to undergo modifications, with the most crucial step being immersion in the pool. The liquid in the pool was actually a blood solution tainted with his brainwaves, except that for these 'birds', there was no need for extended corrosion — they only needed to merge this blood with theirs, and his brainwaves would naturally contaminate theirs.
Of course, King Robin wouldn't comply easily; they were of a kind, always trusting only themselves. Even if they served as someone else's lackeys for a time, they would never be sincere, so King Robin created a little pill to maintain a lucid consciousness.
But unfortunately, utilizing an apparatus to analyze brainwaves, he had long read King Robin's thoughts. Being trapped in the base, King Robin only had access to the equipment there, so it was all too simple to mix something into the pills.
However, if King Robin swallowed the pill without a hitch, he would naturally become suspicious. Again, they were of a kind; in times of adversity, they doubt their foes, but in smooth tides, they suspect their allies.
To put King Robin at ease, he pretended to discover at the last second that King Robin spat out the pill into the pool. But since he ingested part of it anyway, it still contained his blood.
This was another technology associated with the brainwave reading device. His brainwaves persisted in the blood, analogous to a hacker remotely controlling a computer to overwork and overheat, causing an explosion. This portion of the virus-brainwave could reverse-manipulate the brain, causing it to burst.
Mingled with Robin's own blood in due course, the brain's explosive blood would become incredibly corrosive — essentially a bio-weapon.
He set the trigger for the explosion to activate should anyone pry into King Robin's brain, thereby starting the self-destruct program.
Of course, someone would probe into King Robin's brain. The only piece of information he had was that the Professor was a sufficiently professional psychologist.
No psychologist could remain indifferent upon encountering such invaluable research material as King Robin. Typically dressed impeccably, if splattered with such corrosive blood, they would likely end up utterly degraded, their clothes completely eroded, rendering them a sorry sight, provoking their anger, driving them mad.
That was his objective; he needed to divert the Professor's attention to seize the chance to invite a few selected actors to his stage.
By causing serious injury to Arkham Batman through King Robin, leading him into a half-dreaming state required for him to enter the dream, and during the battle, using the connection between Symbionts to broadcast the situation of Arkham Batman to Arkham Knight Jason to agitate Jason's psyche, drawing him into the dream as well — father and son were in place.
He had long known about an item in King Robin's belt, the Colorful Kryptonite Ring. With this item, King Robin had killed the Superman of his own universe, and one of the Kryptonites could trap Superman in an illusion.
When Superman, rushing to save Batman, got hit by the ring, he knew Superman's entry into the dream was inevitable. Despite Superman's desire to save Batman, he would never allow such a dangerous item capable of bringing him down to fall onto the streets below, so he would certainly be affected by the illusions for an extended period — Superman was also in place.
"As for Gordon..." Bruce crossed his arms and smiled, "He is an acquaintance of mine. I didn't kill him."
Shiller knew he was talking about the Gordon from the script, who was likely the same Gordon from the original universe of the Laughing bat, inexplicably not dead, but turned into a tragic character in the script.
"And as for Spider Man..." Bruce looked at Shiller, drawing out his tone, clearly implying something.
"Of course, I sent him in," Shiller said. "It's good to have one more young hero awakened by the Transition script you've painstakingly written, isn't it?"
"The key is, how dare you bet that the script would awaken them, rather than completely destroy them?"
"That's what we're going to discuss next," Shiller said as he put down all the film reels in his hand and picked up a stack of storyboard sketches, tapping the table lightly with his finger. "Did you write this script?
"Of course, to match the level of your student, it was quite difficult for me to make it so crude and childish," Bruce said with a smile.
"If that were truly the case, it would be just fine," Shiller said, shaking his head as if a bit exasperated, then looked up at Bruce. "Childishness and crudeness aren't praiseworthy, but there's also no need for sarcasm, as everyone has those moments."
"In certain circumstances, unrefined artwork lacking polishing has its own charm of simplicity and antiqueness. It may not be heart-shakingly impactful, but at the very least, one can see a trace of the innocence of bravely trying and exploring."
"But this script..." Shiller glanced at the storyboards in hand and continued, "is not crude and childish, but simply poor quality, arrogant, and utterly boring."